Various compositions are known to be useful as treating agents to provide surface effects to substrates. Surface effects include repellency to moisture, soil and stain resistance, and other effects which are particularly useful for fibrous substrates such as fibers, fabrics, textiles, carpets, paper, leather and other such substrates. Many such treating agents are partially fluorinated polymers or copolymers.
Fluorinated polymer compositions having utility as fibrous substrate treating agents generally contain pendant perfluoroalkyl groups of three or more carbon atoms, which provide oil- and water-repellency when the compositions are applied to fibrous substrate surfaces. The perfluoroalkyl groups are generally attached by various connecting groups to polymerizable groups not containing fluorine. The resulting monomer is then generally copolymerized with other monomers which confer additional favorable properties to the substrates. Various specialized monomers may be incorporated to impart improved cross-linking, latex stability and substantivity. Since each ingredient may impart some potentially undesirable properties in addition to its desirable ones, the specific combination is directed to the desired use. These polymers are generally marketed as aqueous emulsions for easy application to the fibrous substrates.
Various attempts have been made to increase the oil- and water-repellency imparted to the substrate and its durability while reducing the amount of fluorinated polymer required, i.e., boost the efficiency or performance of the treating agent. One method is to incorporate blocked isocyanates or melamine resins. However, only limited amounts can be used because these ingredients tend to adversely affect the handle (the feel) of the fibrous substrate. Another approach employs use of various extender polymers. These are typically hydrocarbon polymers in aqueous emulsions, which are blended with the fluorinated polymer emulsion before application to the substrate.
U.S. Pat. No. 7,344,758 discloses an emulsion suitable for imparting oil and/or water-repellency to substrates, containing a fluorinated acrylate copolymer.